PostCondition

Union type representing every kind of post-condition: STX, fungible token, non-fungible token, staking, and PoX.

---

Usage

import { Pc, PostCondition } from '@stacks/transactions';

// Build post conditions with the Pc builder
const stxPc: PostCondition = Pc.principal('STB44HYPYAT2BB2QE513NSP81HTMYWBJP02HPGK6')
  .willSendEq(10000)
  .ustx();

const ftPc: PostCondition = Pc.principal('STB44HYPYAT2BB2QE513NSP81HTMYWBJP02HPGK6')
  .willSendGte(100)
  .ft('ST1PQHQKV0RJXZFY1DGX8MNSNYVE3VGZJSRTPGZGM.token', 'token-name');

// Staking post condition
const stakingPc: PostCondition = Pc.principal('STB44HYPYAT2BB2QE513NSP81HTMYWBJP02HPGK6')
  .willSendLte(1000000)
  .ustxToLock();

// PoX post condition
const poxPc: PostCondition = Pc.principal(
  'STB44HYPYAT2BB2QE513NSP81HTMYWBJP02HPGK6'
).willNotPerformPox();

Reference Link

---

Definition

type PostCondition =
  | StxPostCondition
  | FungiblePostCondition
  | NonFungiblePostCondition
  | StakingPostCondition
  | PoxPostCondition;

See PostConditionType for the wire value each of these serializes to.

---

Availability

Member	Available from
maybe-sent on NonFungiblePostCondition (SIP-040)	@stacks/transactions 7.4.0, Stacks epoch 3.4
StakingPostCondition and PoxPostCondition (SIP-045)	@stacks/transactions 7.5.0, Stacks epoch 4.0

Staking and PoX post-conditions are specified in SIP-045 §3.4.3. The @stacks/transactions JSDoc labels these SIP-044; the two SIPs activated together.

---

StxPostCondition

interface StxPostCondition {
  type: 'stx-postcondition';
  /** Address sending the STX (principal address or contract-id) */
  address: string;
  /** Comparator: 'eq' | 'gt' | 'gte' | 'lt' | 'lte' */
  condition: FungibleComparator;
  /** Amount in microSTX */
  amount: string | bigint | number;
}

---

FungiblePostCondition

interface FungiblePostCondition {
  type: 'ft-postcondition';
  /** Address sending the asset */
  address: string;
  /** Comparator: 'eq' | 'gt' | 'gte' | 'lt' | 'lte' */
  condition: FungibleComparator;
  /** Asset string: '<contract-id>::<token-name>' */
  asset: AssetString;
  /** Amount of tokens */
  amount: string | bigint | number;
}

---

NonFungiblePostCondition

interface NonFungiblePostCondition {
  type: 'nft-postcondition';
  /** Address sending the asset */
  address: string;
  /** Comparator: 'sent' | 'not-sent' | 'maybe-sent' */
  condition: NonFungibleComparator;
  /** Asset string: '<contract-id>::<token-name>' */
  asset: AssetString;
  /** Clarity value identifying the specific NFT */
  assetId: ClarityValue;
}

maybe-sent was added by SIP-040. It always passes, and still counts as covering that NFT instance under Deny or Originator mode.

---

StakingPostCondition

Guards staking STX or modifying staked STX for a principal. For example, the pox-5 stake, register-for-bond, and stake-update calls. Uses the same comparators as StxPostCondition.

interface StakingPostCondition {
  type: 'staking-postcondition';
  /** Address staking the STX (principal address, contract-id, or 'origin') */
  address: string;
  /** Comparator: 'eq' | 'gt' | 'gte' | 'lt' | 'lte' */
  condition: FungibleComparator;
  /** Amount in microSTX */
  amount: string | bigint | number;
}

---

PoxPostCondition

Guards PoX state changes that do not alter locking status. For example, the pox-5 unstake, unstake-sbtc, update-bond-registration, and announce-l1-early-exit calls. Carries only a principal and a condition code.

interface PoxPostCondition {
  type: 'pox-postcondition';
  /** Address whose PoX actions are constrained (principal address, contract-id, or 'origin') */
  address: string;
  /** Comparator: 'will-not-perform' | 'may-perform' | 'will-perform' */
  condition: PoxComparator;
}

type PoxComparator = 'will-not-perform' | 'may-perform' | 'will-perform';

Comparator	Meaning
will-not-perform	The principal must not perform a gated PoX action
may-perform	The principal may or may not perform one; always passes
will-perform	The principal must perform a gated PoX action